1 Field of the Invention
This invention relates in general to an open end wrench, and in particular to an open end wrench head, usually called a crowfoot head and/or flare nut head, which is provided with a removable handle that can be extended for increased torque.
2. Description of the Prior Art
In a conventional open end wrench head with a removable handle, the wrench head is usually provided with a drive hole into which a drive post is inserted for coupling the handle to the wrench head. The open end wrench head is usually provided with rigid jaws joined to a shank or web. The jaws have parallel faces that are used to engage a nut or bolt having straight parallel sides.
In use, torque is applied to the handle and the force is transmitted through the drive post to the sides of the drive hole located in the wrench head. The shape of the drive post corresponds closely to the shape of the drive hole in the wrench head, which is usually square or polygonal, so that rotation of the drive post within the drive hole is very limited. During torque, corners of the drive post will contact the sides of the drive hole. Because only the corners of the drive post contact the drive hole, the corners will tend to wear off. The sides of the drive hole, which are flat surfaces, will also tend to round out.
Many removable wrench handles are also provided with extensions. These extensions allow the user to create greater torque by increasing the distance over which force can be applied. These usually consist of a cylindrical shaped primary handle over which a hollow extension can be slid along the length of the primary handle.
Because most open end wrenches employ jaws with parallel faces, the user is generally required to remove the wrench from the nut after each stroke and reposition it on the nut. However, there are several patents for open end ratcheting type wrenches. One open end wrench head that provides ratcheting action is shown in U.S. Pat. No. 4,889,020. These open end ratchet type wrenches allow the wrench to be slid around the nut in one direction while locking onto the nut in various drive positions when applying torque in an opposite direction.